An internal investigation at Deutsche Bank has found that incomplete data related to a carbon tax fraud probe were handed over to prosecutors, German magazine Der Spiegel said on Friday.
The probe is one of several legal headaches with which Germany's biggest lender is grappling.
The bank declined to comment on the report in Der Spiegel, Germany's most influential weekly news magazine.
The magazine, which did not cite any specific sources for its information, said some data relevant to the prosecution's probe might have been deleted by an automated process. It did not say how much data might have been missing.
The magazine did not say anybody had been accused of wrongdoing.
The report said the investigation was conducted by Deutsche Bank's internal auditing department and a law firm the company had hired.
Deutsche Bank is also dealing with allegations in Britain and the United States that it was among those complicit in manipulating Libor interest rate benchmarks and had mis-sold subprime assets during the 2007-2009 global financial crisis.
(Reporting by Maria Sheahan and Edward Taylor; Editing by Matthew Tostevin)